Panel board and panel-board construction



May 9. H. F. STARRETT PANEL BOARD AND PAEL BOARD CONSTRUCTIQN Original Filed Nov. 10, 1919 12 sham-shut 1 May 24; 1927.

' 1,629,645 H. F. STARRETT PANEL BOARD AND PANEL BOARD CONSTRUCTION Original Filed Nov. 10, 1919 12 Sheets-Sheet 2 May 24, 1927. 1,629,645

H. F. STARRETT PANEL BOARDAND PANEL BOARD CONSTRUCTION Orizinal Filed Nov. 10, 191

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Original Filed Nov 10. 1919 12 Sheets-Sheet 6 May.

H. F. STARRETT PANEL BOARD AND PANEL BOARD CONSTRUCTION Orizinal Filed Nov. 10, 1919 JAW'JM 4 1 2 927 H. F. STARRETT PANEL BOARD AND PANEL BOARD CONSTRUCTION Criminal Filed Nov. 10, 1919 12 Sheets-Sheet 8 "May 24, 1927; 1,629,645

H. F. STARRETT PANEL BOARD AND PANEL BOARD CONSTRUCTION oriiinl Filed 10 .v 1919 12 Sheets-Sheet 9 Jae/i257?" I 3,629 6% y 241 1927* H; STARRETT V 9 PANEL- BQARDMID PANEL BOARD CONSTRUCTION Origin??? Fi e OV. 10, 1919 12 Sheets-Sheet 10 l, 29 May H. F. STARRETT 6 PANEL BOARD AND PANEL BOARD CONSTRUCTION n 2/5 5 i mil:

1,629, 5 7 May 1927 H. F. STARRETT 64 PANEL BOARD AND PANEL BOARD CONSTRUCTION Original Filed Nov-1o, 1919 12 Sheets-Sheet 12 12 ,74 fig 445 33 2 255 25 253 252 Patented May 24, 1927. I I l UNITED STATES PATENT OFFICE.

HENRY F. STARRETT, OF CHICAGO, ILLINOIS, ASSIGNOR T STARRETT MANUFACTUR- ING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 01E ILLINOIS.

PANEL BOARD AND PANEL-BOARD CONSTRUCTION.

Application filed November 10, 1919. Serial No. 337,068; Renewedl'une 16, 1924.

This invention relates to panel boards I quired for the construction of the panel and panel board construction and more board, whichis constructed according to the particularly to panel boards used in electric teachings of this invention, can be made in lighting systems, and in systems of rcsiquantity by the manufacturer'with conse- 5 dence, apartment, factory, and all other types quent lessened cost and can be carried in f b ildi i i stock to enable quick assembly at minimum This invention is a further development of The manufacturer can consequently the invention disclosed in my Pat t N establish throughout the country branch dis- 1,294,185, issued February 11th, 1919, and tributing houses where these various comio comprises an enlargement of the knock- "ponent parts can be carried in stock and at down-fo f panel b 1, th it f which. substantially any desired type of which are standardized stock parts which Panel board an b ons ruc ed With a minimay be readily assembled to provide a panel mum of labor and time, Y board of any desired capacity. and adapted The ll'lilnufacturel y Carry in stock at 15 t any one f a l lit f l t i i i the factory and at these branch distributing systems within the regular requirements of houses portable standardized neutral panel h t d 4 units of varying capacity which can be road For the purpose of adapting the standardily united to construct panel boards of a caized stock units to any one of a plurality of pacity larger than any of the standard port- 20 clectriowiring systems, the unit constructable units, and which are adapted to be 7 ed for stock purposes is what maybe termed included by the addition of selected standa neutral unit; that is, a unit comprismg a ardizing parts into anyone of a plurality standard zed base which may be either blank of electric wiring systems. However, since or may carry circuit controlling equipment, these portable neutral units are constructed :5 and which in the condition that it is carried f r in erchangeability and the assembly .in stock is not designed for any particul r thereof is an exceedingly simple operation, type of electric wiring sys'tem. These units, a large panel board can be maintained, if however, are designed and constructed so desired, in a portable disassembled or that they possess an inherent capacity for knockdown state until it has-been trans- ::0 development, by the addition of other stand, vported to the place where it is to be installed.

ardized means, whereby, when assembled The panel board problem, including all its into a panel board containing ither on ditferent variable features, as for example,

a plurality of said neutral units, the units can capacity and ultimate method of intercon- 'be interconnected by the use of said standnection to the power leads and distributing ardized means into any one of a plurality System, is thus reduced to a manufacturing of electric wiring systems. The panel board and C0mm9ICifi1 p p ion d removed unit system described herein, therefore, disfllmOSt e y from the domaln 0f tinguishes from the invention disclosed in g i any-aforesaid patent, primarily in that in Brlefiy stated, a built up panel board of 40 the present invention the unitary stock elethe type hereinafter specifically described ments of the systems are neutral with rempr s either or a p ura ty o standspect to the ultimate panel board electric aldbasic neutral units qu pp d with either wiring system and can be adapted and conbranch unit fuse receptacles only or with liccted by standardized means into any one branch circuit switches and fuse receptacles.

45 of a plurality of'such systems; wh r i These units are constructed in varying cathe invention of my aforesaid patent each pacities, preferably O r-c rcuit, S X-ClPClllt, unit is individual to and adapted to but'one eight-circuit, and ten-circ1iit units, whichparticular form of panel board electric wirunits may used either individually or in ing system. The inherent improved conany desired combination to obtain a panel struction of the units, standardized co'nductboard of the desired capacity. Each of said ing bars andmain bus bars of this system units, depending upon the ultimate electric likewise serves to better adapt the system for wiring system to be utilized, is also fitted the construction of panel boards of into receive standardized conducting bars creased current carrgi 'ing capacity -which serve as the interconnecting links be All the coinponent elements and parts retween the conducting bars of the neutral barrier unit and the main bus bars. Associated with each panel board, depending upon the ultimate service desired, is a tail unit such as described in my aforesaid patent, which tail unit carries the terminal equipment, either fuses or switches or combination fuses and switches, or an other desired equipment, adapted to t e particular type of wiring system whichis to be connected to the panel. board. The system, therefore, contemplates and requires neutral basic standardized units for each capacity of unit that'it is desired to carry in stock for two equipmentsthe one in which fuse recepta-' cles only are required, and the other in which combined 'fuse receptacles and switches are desired. With these units, the standardized conducting bars and suitable common bus bars, which can be connected to the equipment without the necessity of any lateral. bends, any desired capacity of panel board can be constructed and equipped for connection into electric distributing systems of either the two-wire, three-wire, threephase, four-wire three-phase or convertible two to three-wire and three to two-wire type and all commercial variations therefor.

It is one of the principal objects of this invention, therefore, to produce a system of standardized commercial production in the panel board art whereby panel boards of any capacity can be built up from knockdown standardized'units and whichunits, when thus assembled into a panel board, can be combined with standardized means so that they can be interconnected into any one of a plurality of commercial electric wiring systems.

It is another object of this invention to so construct and design these standardized units and the associated standardized interconnecting means that the standardized commercial bus bar strap can be used to interconnect the equipment of the units without the necessity of. an lateral bends in the bus bars, tl. :rebyavoi ing the complicate form of the bus bar strap. This obviously reduces the work of constructing the main bus bars for the panel board to the exceedingly simple and inexpensive operation of.

and making occasional vertical bends.. nsequently, the necessary main bus bar can be readily cut and fitted without complicated tools, and this operation can be easily, readily, and cheaply performed either at the factorypr at the branch distributing house.

A further object of this invention consists in the production of an improved form of basic unit of the neutral type.

Another object comprises the production of an im roved construction of panel board rame.

Another object consists in the production of an improved form of switch cover plate cuttmg the straio standardized forms of circuit" utilized with the switches and panel boards of this type when the dead front type of panel board is desired.

A still further object comprises the provision of simple means whereby the panel board can be easily and properly centered and positioned in'the panel box.

Other objects and advantages of the invention will be apparent from the accompanying description setting forth in more detail such objects, features," and advantages and the manner in which the same are realized and also from the accompanying drawings illustrating an embodiment of the invention, as well as modifications of certain features thereof.

' Referring to the drawings- Fig. 1 is a view in front elevation of an assembled panel board positioned in a panel box with the inner door of the panel box cover thrown open to expose to view the branch circuit switches;

Fig. 2 is a like view in front elevation with the main door of the panel box opened to expose the circuit controlling equipment of the assembled panel board;

Fig. 3 is a similar view in front elevation with the cover of the panel boxremoved and illustrates the method of positioning the assembled panel board in the panel box and the manner in which the barrier frame is positioned around the assembled panel board;

Fig. 4 is a vertical section taken on the plane indicated by the line 4-4; of Fig. 3 looking in the direction of the arrows;

Fig. 5 illustrates a plan view of a neutral unit with some of the circuit controlling equipment assembled thereon;

Fig. 6 is a similar view with the current conducting bars utilized to wire the circuit controlling equipment on the front of the unit to the rear thereof removed;

Fig. 7 is an enlarged detailed view of a section of the rear face of said unit illustrating the perforations molded in said unit to receive the conducting bars which carry the circuits from the controlling equipment mounted on the front of the unit to the rear face of said unit;

Figs. 8 and 9 are enlarged perspective views of the conducting bars used to conduct the circuits of the. apparatus mounted on the front of the unit to the rear face of said unit;

Fig. 10 is a plan view of another standardized neutral unit illustrating the flexibility of the said units with respect to the controlling equipment such as knife switches, snap switches, plu -fuse receptacles, and cartridge fuse receptac es;

Fig. 11 is a like view with most of the equipment removed to illustrate in detail the shape and size of the standardized conducting elements used with these 'various ty es of units- Fig stan ardized neutral unit adapted for use with fuse receptacles only; Fig. 14 being adapted to "fuses of the cartridge type and Fi 15 to fuses of'the plug type;

Fig. 16 is a section taken on the plane represented byline 16-16 of Fig. 14 looking in the direction of the arrows;

Fig. 17 is a section taken on the-plane represented by'theline 17 17 of. Fig. 15 lookingvin the direction of the arrows;

' ig. 18 is an illustration in perspective of the housing utilized to cover the branch circuit conducting terminals mounted on the face of the units;

Fig. 19 is a vertical section taken through the center of one of these units with the said housing in position;

Fig: 20 is a plan View of the metallic rcenforcing frame used with the standardized units;

Fig. 21 is a side elevatiomthereof;

Fig. 22 illustrates the side view of one of the barrier units and shows the means utilized for re-enforcingsaid side and interconnecting various sections thereof;

Fig. 23 is a view in perspective illustrating the corner iron which receives the sides of the barrier frame and illustrates the method of connecting the re-enforcing member of the side with said corner iron;

Fig. 24 is a vertical section through the cover of the panel box illustrated in Fig. 1

and illustrates the means utilized for preventing access to the fuse receptacles when the inner door of the cover of the panel box only is opened;

Fig. 25 is an enlarged perspective view of the metallic receiving pockets used to position the assembled panel board in the panel box enclosure;

Fig. 26 is a vertical section .through thebranch switch circuit cover plates and illustrates the means for interconnecting and interlocking these plates whereby the individual plates when assembled are rigidly held in position and give the general appearance of one continuous late;

Fig. 27 is a rear view of t 1e upper portion of the assembled panel board shown in Figs. 1 to 4 inclusive with-the main bus bars and the conducting bars used to connect the main bus bars to the neutral units removed;

Fig. 28 is a rear view of the assembled panel board shown in Figs. 1 to 4-inclusive assembled with standardized means to adopt the board to a two-wire distributing system;

Figs. 29 and 30 are enlarged perspective views of the standardized conducting bars used to interconect the main bus bars and the conducting bars or plates of the neutral unit for a two-wire distributing system; 7

Fig. 31 is a rear view of the panel board illustrated in Figs. 1 to 4 inclusive assembled with standardized means for a three-Wire distributing system.

Fig. 32 is aplan view of the tail unit used with the assembled panel board when wired for a. three-wire or three-phase distributing system.

Fig. 33 isa plan view of the tail unit utilized with the panel board adapted for a three-wire distribution system wh n converted to a two-wire distributin system;

Figs. 34 to 37 inclusive are en arged perspective views of the standardized conducting bars used to interconnect the conductas ing bars or plates of the neutral units with the main bus bars ofthe panel board-when adapted tor a three-wire distributing system;

Fig. 38 is a view in side elevation of a common bus bar;

Fig; 39 is a rear view of the assembled panel-hoard illustrated in Fi s. 1 to 4 inclusive assembled with stan ardized conducting means for a three-phase distributing system;

Figs. 40 to 43 inclusive are enlarged perspective views of the standardized conducting bars used to interconnect the conducting bars or plates of the neutral units with the main bus bars of a three-phase distributing system;

Fig. 44 is a rear view of the assembled panel board illustrated in Figs. 1 to 4 inclusive assembled with standardized means for a four-wire three-phase distributing system;

Fig. 45 is a front elevation of the tail unit used with the assembled panel board when wired for a four-wire three-phase distributing system; and v Figs. 46 to 49 inclusive are enlarged perspective views of the conducting bars used to interconnect the conducting bars or plates of the neutral units with the main bus bars. 11

According to this invention a plurality of assembled units are provided which may be manufactured in stock form and which may be used for supplying a panel board for any capacity desired and adapted to be built u for interconnection into any one of a desired plurality of electric wiring systems. As hereinbefore stated, itis preferred to construct these units for a capacity of four, six; eight, and ten circuits, but for the sake of brevity in the description,-and in order to "curtail the number of necessary illustrabled panel board is consequently designedfor an ultimate capacity of twenty circuits, and if any other capacity is desired, the standardized units of four, SIX, eight, and

ten circuits can be readily combined to obtain any desired ultimate capaci As illustrated in these figures, bled panel board is positioned in a panel box enclosure consisting of the base portion 14 and the cover portion 15. The cover portion 15 is secured to the flanges 16 on the base portion by means of screws such as 17. The cover portion 15 is equipped.with a double door, the outer door 18 being of a size suflicient to cover the fuse receptacles and switches mounted on the panel board, and the inner door 19 being of a size sufficient to cover only the branch circuit switches. The inner door 19 is hinged to the.

outer door at 20 and 21; whereas, the outer door 18 is suitably connected to the cover frame 22 by means of hinges such as 23. The cover frame 22 serves as a cover for the gutter. 24 surroundin the assembled panel card, the panel boar being separated from the gutter by a barrier frame 25 consisting of the end pieces 26 and 27, and the side pieces 28 and 29.

-The frame 22, as will be evident from Figs. 2 and 3, serves to cover completely the gutter- 24 and the enclosing barrier frame 25 whereby all the branch fuse receptacles and switches will be exposed to view when the outer door 18 is opened, as illustrated in Fig. 2, and the branch circuit switches only will be exposed to view when the inner door 19 is opened. The inner door 19 is eguip ed with a suitable catch 30 by means 0 w ich it can be fastened to the outer door, and preferably this door is not fitted with a lock so thatthe branch circuit switches covered by said door will always be accessi le. The outer door, on the other hand, equipped with a lock 31 to lock this door to the frame 22, and whereby access to the fuse receptacles can be obtained only by those who have possession of the key,

which key will be retained by the expert electrician or those authorized to make fuse plu changes.

ie individual standard units 10, 11, 12, and 13 are mechanically connected, as here'- inafter described, to suitable channel bars. such as 32 and 33, which channel bars are secured to the bottom of the base 14. by means of screws such as 34-. It will consequently be apparent that the assembled panel board as a whole can be readily removed or positioned in the panel box enclosure. In order to facilitate the positioning of the assembled panel board in the panel t tile assent box enclosure so that the respectiye doors 18 and 19 and the frame 22 of the cover 15 will be properly positioned and centered.

with respect to the panel board, mechanical receiving pockets or shoes such as 35 are fitted on the bottom of the base 14 of the housin as will be more specifically hereinafter diascribed.--

,As illustrated in Figs. 1 to 4 inclusive, the assembled panel board consists of the portable inter-fitting basic units 10, 11, 12, and 13 and a suitable tail unit such as 36, the tail unit being separated from the rest of the panel board by a barrier 37. The assembled panel boards consisting of the standardized units 10, 11, 12, and 13 consequently have their ends enclosed by the barriers 26 and 37, which snugly fit against the end of the two units 10 and 13 respectively and thus close oil the end pieces of apparatus on these units from the gutter 24 and the tail unit respectively. In order to completely enclose all potential and current carrying parts of the panel board, so as to prevent both accidental and deliberate contact therewith, the branch circuit switches are covered with plates such as 38, through which the operating elements of the switch mechanisms project. These cover plates for the switches will be described more in detail hereinafter.

In order to shut off completely the fuse receptacle mounted on the units, from the individual opening provided by the inner door 19 used for the purpose of operating the switches, the outer door 18, has secured thereto the downwardly extending flanges 39 and 40, preferably constructed of sheet steel (see-Figs. 2 and 24). These flanges, when the outer door is closed, completely close the space between theswitch covers 38 and the door, and thus prevent'any deliberate effort to reach the fuse receptacle and fuse plugs, and likewise prevent the accidental .droppin of foreign matter into the space occupied y the fuse receptacles positioned on theunits. The flanges 39 and 40 are tapered asshown in Fig. 24, whereby the desired sized opening for the switches may be obtained without unnecessarily increasing the width of the panel board to prevent interference between the fuse receptacles and their associated fuse plugs and ,the flanges or partitions 39 and 40.

structurally, all the basic units illustrated are substantially the same, differing only in capacity and possibly in width, the units which are to be used forcfuses only being preferably made somewhat narrower than the ones with which switches and fuse receptacles are to be used, so that a description of one of said units will serve for all.

The standard portable basic neutral unit used to build up the panel board of the four circuit capacity is illustrated in Figs.

- a fiat slab or base 4l of insulating material,

preferably of some non-brittle material, such as pitch-asbestos compound which can be readily molded in the desired shape or any other such suitable insulating material that can be obtained on the market. Such a molded base possesses the advantages of being light in weight and because of he inherent'advantages of the material employed can be made in much smaller sizes and weight for the same capacity of panel board than slate or like brittle material. Likewise, such a molded base, when it leaves the mold, is a finished article equipped with all the perforations and any special shapes which are desired in the finished article.

The base 41 (see Figs. 5, 6, and 27) if provided with aseries of perforations such as 42, which are" adapted to receive screws 43, the threaded ends of which are connected to conducting bars such as 44 mounted on the frontface of the unit. These conducting bars 44 are fitted with threaded apertures such as 45 which are adapted to receive screws such as 46 of the fuse receptacles 1n- 'terconnectlng the center contact of said fuse receptacles with the conducting bars 44, the screw 46 constituting the center contact of the fuse receptacle. The threaded shell contact 47 of the fuse receptacle is directly connected to a branch circuit terminal 48, illustrated in Figs. 2 and 10, and to be described more in detail hereinafter.

In addition to the perforations 42 the base unit 41 is equipped with four perforations such as 49, preferably positioned near the four corners of the unit, said perforations receiving screws such as 50 to receive the cross bars 51 of the re-enforcingframe for the unit. The base 41 is also fitted with suitable indentations in its top surface under each one of the perforations 45 fitted in the conducting bar such as 44 mounted thereon to receive the ends of the screws such as 52. which are used to secure the encuit controlling equipment to the conductingbars.

In addition to the aforesaid perforations, the neutral unit is fitted with a plurality of slots such as 53, one of said slots being provided for each pair of branch'circuit leads.

, These slots on the rear face of the panel board (see Figs. 7 and 12) are enlarged and provided with an outwardly extending sloping or tapering wall 54, said slope or tapel' being provided so that the cpnducting bar 55, which is positioned in each one of such slots 53, can be readily inserted and positioned in proper place through the narrow aperture 56 out into the top face of the standard neutral panel. In a four circuit standard neutral unit, as illustrated in Figs. 5 and 6.;only two complete slots such as 53 are provided, these slots being positioned as Fig. 8.

are provided, said slots being in all respects identical to the slots 53 but only half the width thereof. Consequently, when two standard neutral units are positioned one above the other, the end slots 57 in such units combine to form a slot similar to the slot 5:. The slots 53, as hereinbefore mentioned, are provided to receive the conducting plates or bars 55, illustrated in detail in These conducting plates are fitted with conducting arms, one of which-58- rests on the front face of the panel, and the other of which-59 is positioned in a groove 60 cut in the lower face of the panel. The arm 59 can obviously be either positioned in a groove such: as 60 cut in the back face of the standard unit ormay be designed so as to be placed on the back surface of said unit, under which circumstances the groove 60 can be eliminated. The arm 58 and arm 59, which rest on either side of i the standard unit, are interconnected and integral with the conducting link 61, which is tapered so that the conducting plate 55 can be readily inserted and positioned into the perforation 53 in the base of the standard unit. t

' Conducting plates or bars such as 55 are positioned in all of the perforations 53 and in the built u perforations consisting of two perforations 57 mounted end to end, which combine to make perforations such as 53. Whenever the standard neutral unit is not combined with another standard neutral unit so that the end slot or perforation 57 cooperates with another slot or perforation to form a perforation or slot such as 53, the slot or perforation 57 is equipped with a conducting plate or bar such as 62. (See Fig. 9.)

The conducting plate 62, as will be evident from Figs. 8 and 9, is alike in all respects to half of the plate 55 when said plate 55 is divided along its median/line. Thus, the conducting plate 62 is fitted with an arm 63 which lies on the front face of the panel unit and an arm 64 which rests in a slot cut in the rear face of the standard unit, each ofsaid arms being of half the length of' the corresponding arms 58 and 59 respectively of the conducting plate 55. The arms 63 and 64 of the plate 62 are integral with and interconnected by a conducting strap 65, which strap 65 is of half the width of the corresponding element 61 of the plate 55.

The upper arm 58 of the conducting plate 55 is fitted with-threaded perforations such as 66 which are adapted to receive the screws 52, which interconnect the terminals of the switch such as 67 with the conducting bar 55, and thus extend the terminal connection of the switch from -the front to the rear of the standard neutral panel board unit. The conducting plate 62 is fitted with like per forations serving the same purpose.

The arm 59 is provided with threaded perforations 69 adapted to receive standardized conducting means ada ted to lnterconnect the circuit contro ling apparatus mounted on the. front of the standard panel unit with the main bus bars, as will be hereinafter described. The conducting plate 62 is fitted with a like threaded perforation 69.

The plates 55 and 62 are held in position, after being inserted in the'standard neutral panel unit, in any suitable manner,but preferably by means of screws such as 73, which will be readily apparent from inspection of Figs. 5 and 7 The slots 53 on the rear face of the base unit 41 are provided with elongated depressionssuch as 70 and 71, which extend along the rear face of the unit 41. These depressions are fitted with perforations such as 72 which extend to the front face of the unit 41 and which receive the screws such as 73 for securing the conducting plates or bars such as 55 and 62 to the unit 41.

As hereinbefore stated, each standard neutral panel unit comprises an insulating base 41 and has secured thereto, by meanspf the screw 50, the re-enforcing bars 51 which extend across the entire rear face of the base 41. These bars 51 are preferably made of steel and, in addition to re-enforcing the base 41 and increasing its rigidity, these bars serve as the interconnecting means for the lateral mounting plates 76 which are"se cured to the bars 51 in any suitable manner, preferably by welding (see Figs. 20, 21 and 24).

The mounting plates 76 consist of a strap of metal, preferably steel, extending along the lateral edges of the'base 41- of the unit and are of a substantially section, the

upper arm 77 of which is attached to the cross re-enforcing bars 51 and the lower arm 78 of which, provided with an elongated perforation 79, is utilized to mount the panel unit on the channel irons 32 and 33 heroinbeffore referred to.

It will now be evident that in assembling a unit of the type illustrated in Figs. 5 and 6, the insulating base 4.1 is first fitted with the re-enforcing members 51 by means of the screws 5C, whereby the mounting 6, the standard push button switch, such as 67, has two of its terminals connected, one to the arm 58 of the conducting plate 55,

and the other to the arm 63 of the conducting plate 62. The other two terminals of the switch 67 areconnected to conducting bars such as 44. Likewise connected to the conducting bars 44 are the screws 46 which constitute the center contact of the two fuse receptacles 48 associated with each one of these push button switches 67.

. To those skilled in the art it will be evident from the connection, shown in the upper right corner of Fig. 5, of the fuse receptacle and switch how this apparatus for the entire unit is connected to the various connecting bars and plates associated with the unit. It will also be apparent that the conducting plates 55 serve as a common conductor for one terminal of two circuits. In other words, one tern'iinal of each of two adjacent switches are connected to the arm 58 of a common conducting plate 55. The shell contact of the fuse receptacles is carried out to the branch circuit terminals 48 at the edge of the panel unit in any suitable way. preferably bywa conducting bar such as illustrated in Figs. 1 and 10. Obviously any one of a large variety of means could be used for wiring the shell contact of the fuse receptacle to the edge of the board and a detailed description of the particular manner in which this is done in the embodiment illustrated is, therefore, not essential. The switches such as 67 when mounted on the panel unit are preferably enclosed in an insulating sleeve such as 75, the details and functions of which are described in my co pending application Serial No. 337,069, ontitled PaneLboard and panel-board construction filed of even date herewith.

When the circuit controllingapparatus, such as fuses and receptacles. is mounted on the face of the panel unit and interconnected to the conducting plates, such as 44, 55, and 62, the unit is completely assembled in its neutral condition and is adapted to be titted by the use of standardized conducting means for interconnection with common bus bars adapted to be wiredinto any one of a plurality of electrical wiring systems.

The perforations-and slots with which the insulating base 41 of the standard unit is equipped are so designed and arranged that. said unit can be readily fitted and equipped with either the push button type of switch, the knife blade switch, or with the fuse rcceptacles for plug fuses or cartridge fuses.

Obviously a panel .unit equipn'ient would ordinarily be fitted with but one type of equipment. but in order to clearly illustrate the flexibility of the unit audits adaptallll l-Ju

bility to various'types of circuit controlling apparatus, such as for example, push button switches, knife blade switches, and plug and cartridge fuses, Figure 10 has been included to show a panel with a composite equipment. This figure illustrates a four circuit unit in which two of the circuits are provided with knife blade switches and cartridge fuses and two with push button switches and plug fuses.

Fig. 11 shows the front view of the panel unit with all the apparatus, with the exception of one knife blade switch removed, whereas Fig. 10 illustrates the same panel with the circuit controlling apparatus in position. From .an inspection of Fig. 11. it will be evident that the same conducting bars 44 used in Fig. 5 are used in this instance for the push button switch. The same conducting plates 55 and 62 are utilized to carry the circuit of the circuit controlling apparatus mounted on the, front of the unit to the rear of the unit. For the push button type switch. the terminals of the switch are secured directly to the conducting bars such as 44, 55. and 69.; whereas, for the knife blade switches, as illus- -trated in Fig. 12, the clip contacts 80 are secured to the conducting plates 62 and 55 respectively by a screw such as 81 extcnd ing through a standard perforation 81' in the insulating base 41 and the standard threaded perforation in the conducting plates 62 and 65, andis held in place by a conducting plate 82 shown in perspective in Fig. 13, which is fitted with a threaded aperture 83 to receive the end of the screw 81. The plate 82 rides over the base plate 84 of the clip contacts 80, thereby holding the clip contacts in position, and the clip contacts are prevented from turning by means of the downwardly extending arm 85 of the plate 82, which'fits into a slot 86 provided in the base 41. e

The tubular fuses are secured to the base 41 by means of the standard commercial clip contacts ordinarily used in the art, which contacts are formed integral with conducting bars such as 87 and 88. The conducting bars such as 87 are fitted with the threaded perforations 89 and9 0, the perforation 89 fitting over the standardized perforation 42 in the base 41, which are adapted to receive the screws such as 43 to secure the conducting bar 87 and its associated clip to the unit. The bar is also fitted with the threaded perforation 90 adapted to receive the clips for mounting the blades of the knife blade switch. In alike manner the conducting barand'its associated clips 88 are equipped with threaded perforatons91 for securing these bars 88 to the base 41. v

It will now be evident from the descriptions of Figs. 5 to 13 inclusive that the standard neutral panel is perforated and slotted .to receive standardized conducting bars and plates which are adapted to cooperate with suitable interfittings to directly interconnect circuit controlling apparatus of the switch and fuse type illustrated in these drawings with conducting bars or plates extending to the rear face of the unit. Also that the equipment is interchangeably mounted on the face of said units. \Vhen the units are thus equipped with this circuit controlling apparatus of the type desired, the circuits of which are carried to the rear face of the standard units, the said units are in a condition as to the ultimate circuit wiring, which may be termed neutral. inasmuch as they are not fittedin this condition to be wired into any particular type of electrical wiring systems. To adapt such a neutral unit to any one of a pluralityof commercial electrical wiring systems, the conducting plates 55 and 62 are interconnected and associated with standardized conducting means specific to each particular utilized inasmuch as fewer perforations in the said base are necesary because of the elimination of the switches. much as the switches are omitted, it will be evident that the base can be made considerably narrower, said decrease in the width of base being equivalent to the space ordinarily occupied by the switch. Obviously the bases which are equipped for fuses only can be made of the same width as the bases which carry switches and fuses. but in view of the waste of material involved, and inasmuclr as it. very seldom, if ever. would occur that an assembled panel board consist-- ing of units in which fuses only are used on some of the units and. fuses and switches on the other would be desired. it is preferred to make the units carrying fuses only of a narrower width, as illustrated in Figs. 14

to 17 inclusive. The units there illustrated consist each of insulating bases 92 fitted with a re-enforcing frame equipped with lateral mounting plates 93 similar to those described hereinhefore in connection with the unit carryingswitchcs and fuses.

Fig. 14 shows such -a'-. base 92 equipped with fuse receptacles to take fuses 94 of the.

cartridge type. This base is fitted with Further, inas-.

perforations such as 95 (see Fig. 16) to receive the conducting lates such as 96, said plates carrying suitab e perforations such as 97 on the arms 98, which rest on the front face of the plate 92 to receive the fuse clips 99. The front face of the plate 92 likewise carries the terminals conducting plate 100 fitted with the fuse clips 101,- the terminal clip plate 100 being titted with a tread'ed aperture 102 by means of which it is sccured to the insulating base 92, by means of a screw extending througlr from the rear face thereof. The base is also titted with conducting plates such as 90' which are just half the size of a conducting plate 96, the division being on the n'iedian line of the plate 96. Each of the conducting plates 96 and 96', as illustrated in Fig. 16, is fitted with an arm 104 resting on the rear face of the base 92.

In order to cover all perforations such as 95 cut in the base 92, a strip of insulating material 105 is secured to the front face of the base 92 by means of screws such as 100, the said plate 105 resting directly on the face of the plate 92 and completely obscuring the perforations 95, as will be evident from Fi ares 14 and 1G.

ig. 15'illustrates a panel like Fi 14 equipped with receptacles for plug fuses In this instance the conducting bars 107 and 107, which carry the circuit from the front face of the base 92 to the rear face thereof and the upper arms thereof 108 are changed in design to meet the conditions necessary to receive the plug fuse receptacles.

. In other respects this unit is the same as the unit shown in Fig. 14, with the one exception that the plate 109, which covers the perforations 95 adapted to extend the, conucting plates 107 and 107' to the rear. of .the board. is made considerably wider and abuts against the edges of the insulating bases such as 110 of the lug fuse receptacles. The plate 109 in this instance, therefore, insulates and covers all the current and potential carrying conductors exposed on the front face of the, base 92 between the fuse receptacles mounted on either side of the unit. With this plate coverin obscurin these conductors am the use'of the housing for the terminal conductors illustrated in Figs. 18 and 19, hereinafter to be described,-the unit illustrated in Fig. 15 becomes a dead front unit in which all the current and potential carrying parts are completely covered.

Referring now to Figs. 18 and 19,'it will be observed that the plug fuse receptacle 74, which itis preferred to use with this type of equipment, comprises a base portion 112 which is fitted at its forward endwith a square aperture 113, said aperture communieating t rough a cylindrical aperture with the top face of a flange 116 integral with the fuse receptacle 74. The cylindrlcal aperture illustrated in the upper left-hand fuse recompletely is adapted to receive a screw such as 114, which cooperates with the squarenut 115 fitted in said aperture 113. The positioning of the square nut 115 in the uare aperture 113 permits thetightening o the screw 114 on said nut, inasmuch as the nut is prevented from rotatin in the square aperture because the size of t e aperture is just large enough to accommodate the square nut. The screw 114 and its associated nut 115 are utilized to secure to the flange 116 of the receptacle the housing or covering 117 which functions to completely cover the terminal connections of the fuse receptacle, as clearly ccptacle of Fig. 15 and the fuse receptacles illustrated in Figs. 2, 5, and 6. l

The housing 117 is provided with an upper flat face 118 which is provided with an enlargement at 119 apertured at 120. The inner surface of said housing is shaped to conform to the contour of the flan e 116 of the fuse receptacle 74. 'Inte ral with the housing is a forwardly exten ing portion 121, the base of which is provided with the slots 122 and-123 whichserve to fit over the fuse receptacle terminalconducting bars 48. The housing 117, as clearly illustrated in Fig. 18, can be removably attachedto the fuse receptacle 112 by means of the screw 114, the screw 114 passing through the aperture 120 and firmly securing the housing 117 to the fuse receptacle by means of'its associated nut 115. Obviously when the housing 117 is secured to the fuse receptacle, the fuse receptacle conducting bar terminals 48 will be completely covered, as clearly illustrated in Fig. 2.

Attention is now directed to Figs. 2, 4 27, 28, 29 and-30 which illustrate an assembled twenty circuit panel board consisting of two' four-circuit and two six-circuit neutral units which have been interconnected by standardized conducting means, so as to adapt the assembled unit to a two-wire electrical distributing s stem.

In assem ling a. panel board of this type, having determined that the ultimate wiring system isi to beofthe two-wire type, the neutral units are selected of a capacity, the summation of which will give the ultimate capacity of the desired panel board. Obviously, any desired capacity of panel board may be built up and assembled and the twenty circuit unit herein shown and described has been selected for illustration purposes merely. Inassembling this twenty circuit panel board, the four neutral units 10, 11, 12, and 13 equipped with the necessary conducting plates and bars suitable for the ultimate type of circuit controlling apparatus which is to be mounted thereon, or,

with this apparatus actually mounted thereon, are assembled into a unitary structure on the mounting channel irons 32and 33 by too 

